安庆大气颗粒物污染外来输送轨迹及源区研究

在对安庆2015~2016年大气颗粒物变化特征分析的基础上,利用HYSPLIT-4后向轨迹模式,采用气团轨迹聚类分析、潜在源贡献因子法(PSFC)和浓度权重轨迹法(CWT),研究了不同季节安庆地区外源污染物传输的路径及潜在源区。结果表明:(1)安庆市大气颗粒物质量浓度存在显著的季节变化,表现为冬季春季秋季夏季,12月份污染最重,7月份污染最轻。(2)影响安庆地区气流轨迹具有显著性季节性变化特征,夏季主要受来自南方和东南方向海洋气流影响,PM10和PM2.5的平均值较低;冬、春和秋季安庆地区受到海洋性气团和大陆性气团共同影响,且以偏西和西北路径的大陆性气团影响最为明显,受沙尘或人为排放因素的影响,对应PM10和PM2.5的平均值相对较高,颗粒物高污染时段与该2类大陆性气流轨迹输送关系密切。(3)安庆颗粒物冬季PSFC值和CWT值最大,夏季最小。PSFC和CWT值2处高值区主要分布在湖北东部、江西北部和湖南南部等带状地区,以及山西、河南中部、山东南部及安徽北部等带状区域。

TRAJECTORY ANALYSIS OF ATMOSPHERIC LONG RANGE #br# TRANSPORT OF PARTICLES IN ANQING CITY

The atmosphere particulate matter characteristics over the city of Anqing(Southwestern Anhui Province, China) between 2015 and 2016 were analyzed in this study. HYSPLIT 4 backward trajectory model was used to simulated the air pollutions transport patterns and potential source area. The results showed:(1) The particulate matter concentrations had significantly seasonal changes, which was high in winter and low in summer. The highest and lowest particulate matter concentrations appeared in December and July, respectively.(2) The air mass trajectory in Anqing area exhibited significant seasonal variation. In the summer, Anqing is dominated by oceanic airflow from the southern and the southeastern regions. In the other seasons, the Anqing area is affected by the oceanic air mass and the continental air mass. The continental air masses could be divided into the western and northwest path, commonly corresponding with heavy air pollution events in Anqing.(3) The PSCF and CWT values were also higher in winter but lower in summer. High PSFC and CWT values air mass mainly from two stripe areas, one area involved the eastern Hubei, northern Jiangxi and southern Hunan province, another one included the Shanxi, Henan, Shandong and northern Anhui province.